<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        *{
            margin: 0px;
            padding: 0px;
        }
        #header{
            width: 100%;
            height: 100px;
            background-color: darkgray;
        }
        #header img{
            border-radius:50% ;
            margin-left:10px ;
            margin-top: 40px;
        }
        #ceng{
            width: 100%;
            height: 100%;
            position: fixed;
            background-color: black;
            opacity: 0.2;
            display: none;
        }
        #nav{
            height: 100%;
            position: fixed;
            width: 270px;
            z-index: 999;
            background-color: red;
            opacity: 0.2;
            left: -270px;
        }
    </style>
    <script src="../js/jquery-3.2.1.js"></script>
    <script>
        $(function() {
            $("#touxiang").click(function () {
                $("#ceng").css("display", "block");
                $("#nav").css("left", "0px");
                $("#header").css("margin-left", "270px");
            })
            $("#ceng").click(function () {
                $("#ceng").css("display", "none");
                $("#nav").css("left", "-270px");
                $("#header").css("margin-left", "0px");
            })
        })
    </script>
</head>
<body>
    <div id="header">
        <img src="../case2/nav.png" id="touxiang"/>
    </div>
    <div id="nav"></div>
    <div id="ceng"></div>
</body>
</html>